The present invention relates to a process for preparing tobacco flavoring formulations for adding the flavor peculair to the kind of tobacco to tobacco products simultaneously with supression of the unsatisfactory peculiarity thereof, using good tobacco plants as the raw material.
During the process of drying leaf tobacco, its ingredients are subjected to fermentation and chemical action and, hence, to hydrolysis and oxidation. As a result, such ingredients are converted to the flavor ingredients peculiar to the kind of tobacco. Although there is a difference from kind to kind, leaf tobacco produces a sufficient flavor through an aging period in which it is subjected to accumulated fermentation or barreled for 1-2 years. In general, tobacco flavorings serve to enrich the flavor of tobacco by imparting thereto the flavor of their own, and provide tobacco products which suit comsumer's taste.
On the other hand, it is likely that leaf tobacco produced in Japan possesses unsatisfactory peculiarities such as bad smell and taste and, thus, are of deteriorated quality due to an increase in the output per unit area or weather conditions during cultivation, soil conditions, excessive fertilization and other factors.
In view of health-related concerns, there is recently a demand for low-nicotine and -tar tobacco products.
A part of the unsatisfactory ingredients of deteriorated tobacco leaves can be removed by using water, air and heat, with which most raw materials are treated. However, such procedures tend to weaken the flavor of tobacco. Low-nicotine and -tar products or sheet tobaccos using a large amount of vein material are also disadvantageous in that they are lacking in the flavor characteristic of tobacco. Some proposals have been made for preparing tobacco flavorings for adding the flavor characteristic of tobacco to materials lacking in the flavor of tobacco. For example, Japanese Patent Laid-Open Publication No. 51-133496 discloses that pre-treated tobacco leaves are extracted with water or a hydrophilic organic solvent at from normal temperature to 80.degree. C., an extracted liquid from which solid matters have been removed is concentrated under reduced pressure into sauce having a solute concentration of about 50%, and the thus obtained sauce is diluted and added to tobacco products for flavoring.
However, in order to prevent decomposition and dissipation of the flavor ingredients present in the starting tobacco leaves, it is desired that, in the process of extraction and concentration, they be treated at a low temperature while reducing as much as possible the amount of heat applied thereto, thereby extracting the water-soluble flavor ingredients of their own. It has also been found that the addition of the foregoing sauce having a solute concentration of about 50%, which has been diluted, introduces no appreciable improvements into the scent of tobacco and the quality of smoke.
U.S. Pat. No. 3,316,919 discloses that tobacco leaves are extracted with a cold solvent such as cold water by gravity filtration, and the thus extracted liquid is powderized by rapid freezing and drying, whereby a powdery flavor ingredient is obtained without causing decomposition thereof. That powder is added to tobacco products in an amount of 5 to 10 weight % for increased flavoring.
In this case, however, no sufficient results are obtained, unless a relatively large amount of that powdery flavoring is added.